Lindhardt T B, Hesse B, Gadsbøll N
Medical Department B 2142, Rigshospitalet, National University Hospital, Copenhagen, Denmark.
J Nucl Cardiol. 1997 Mar-Apr;4(2 Pt 1):147-55. doi: 10.1016/s1071-3581(97)90064-7.
The purpose of this study was to determine the accuracy of determinations of left ventricular ejection fraction (LVEF) by a nonimaging miniature nuclear detector system (Cardioscint) and to evaluate the feasibility of long-term LVEF monitoring in patients admitted to the coronary care unit, with special reference to the blood-labeling technique.
Cardioscint LVEF values were compared with measurements of LVEF by conventional gamma camera radionuclide ventriculography in 33 patients with a wide range of LVEF values. In 21 of the 33 patients, long-term monitoring was carried out for 1 to 4 hours (mean 186 minutes), with three different kits: one for in vivo and two for in vitro red blood cell labeling. The stability of the labeling was assessed by determination of the activity of blood samples taken during the first 24 hours after blood labeling. The agreement between Cardioscint LVEF and gamma camera LVEF was good with automatic background correction (r = 0.82; regression equation y = 1.04x + 3.88) but poor with manual background correction (r = 0.50; y = 0.88x - 0.55). The agreement was highest in patients without wall motion abnormalities. The long-term monitoring showed no difference between morning and afternoon Cardioscint LVEF values. Short-lasting fluctuations in LVEFs greater than 10 EF units were observed in the majority of the patients. After 24 hours, the mean reduction in the physical decay-corrected count rate of the blood samples was most pronounced for the two in vitro blood-labeling kits (57% +/- 9% and 41% +/- 3%) and less for the in vivo blood-labeling kit (32% +/- 26%). This "biologic decay" had a marked influence on the Cardioscint monitoring results, demanding frequent background correction.
A fairly accurate estimate of LVEF can be obtained with the nonimaging Cardioscint system, and continuous bedside LVEF monitoring can proceed for hours with little inconvenience to the patients. Instability of the red blood cell labeling during long-term monitoring necessitates frequent background correction.
本研究的目的是确定非成像微型核探测器系统（心脏闪烁仪）测定左心室射血分数（LVEF）的准确性，并评估在冠心病监护病房住院患者中进行长期LVEF监测的可行性，特别涉及血液标记技术。
在33例LVEF值范围广泛的患者中，将心脏闪烁仪测定的LVEF值与传统γ相机放射性核素心室造影测定的LVEF值进行比较。在33例患者中的21例中，使用三种不同的试剂盒进行了1至4小时（平均186分钟）的长期监测：一种用于体内，两种用于体外红细胞标记。通过测定血液标记后最初24小时内采集的血样活性来评估标记的稳定性。在自动背景校正的情况下，心脏闪烁仪LVEF与γ相机LVEF之间的一致性良好（r = 0.82；回归方程y = 1.04x + 3.88），但在手动背景校正的情况下一致性较差（r = 0.50；y = 0.88x - 0.55）。在无室壁运动异常的患者中一致性最高。长期监测显示，上午和下午的心脏闪烁仪LVEF值之间无差异。大多数患者观察到LVEF有大于10个EF单位的短期波动。24小时后，两种体外血液标记试剂盒的血样物理衰变校正计数率平均下降最为明显（分别为57%±9%和41%±3%），而体内血液标记试剂盒的下降较少（32%±26%）。这种“生物衰变”对心脏闪烁仪监测结果有显著影响，需要频繁进行背景校正。
使用非成像心脏闪烁仪系统可以获得相当准确的LVEF估计值，并且可以在患者几乎没有不便的情况下连续进行数小时的床边LVEF监测。长期监测期间红细胞标记的不稳定性需要频繁进行背景校正。
